1. Field of the Invention
The present invention relates to a safe guarding assembly, and more particularly relates to a safe guarding assembly for a grinding gun that can be used safely.
2. Description of Related Art
With reference to FIGS. 7 and 8, a conventional grinding gun is used to grind and polish surfaces of wood or metal and has a casing (50), a drive shaft (52), a transmitting shaft (51), a clutch shaft (53), a spring (54), a cover (55), a clamping tube (56) and a protective cap (57).
The casing (50) is hollow and has an external surface, a front end and a rear end.
The drive shaft (52) is rotatably mounted in the casing (50) and has a rear end and a front end. The rear end of the drive shaft (52) extends out of the rear end of the casing (50) and is connected to a motor.
The transmitting shaft (51) is rotatably mounted in the casing (50) and has a rear end, a front end, a diameter, a mounting rod (512) and a threaded pipe (511). The mounting rod (512) is axially formed on and protrudes from the front end of the transmitting shaft (51) and extends out of the front end of the casing (50) and has a diameter smaller than that of the transmitting shaft (51) and a front end. The threaded pipe (511) is formed on and protrudes from the front end of the mounting rod (512) and has an inner thread and a diameter smaller than that of the mounting rod (512).
The clutch shaft (53) is rotatably mounted on the external surface of the casing (50) to control the transmitting shaft (51) connecting to or separating form the drive shaft (52).
The spring (54) is mounted around the threaded pipe (511) of the drive shaft (51) and has a front end.
The cover (55) is mounted around the mounting rod (512) and the threaded pipe (511) of the transmitting shaft (51) and has an inner surface, a front end, a rear end, a conical hole (551) and a flange (552). The inner surface of the cover (55) presses against the front end of the spring (54). The conical hole (551) is formed through the front end of the cover (55) and aligns with the threaded pipe (511) of the transmitting shaft (51). The flange (552) is formed annularly on and protrudes from the rear end of the cover (55).
The clamping tube (56) is mounted securely in the transmitting shaft (51) and has an inner end, an outer end and a collet (561). The inner end of the clamping tube (56) is mounted securely in the threaded pipe (511) of the transmitting shaft (51). The outer end of the clamping tube (56) extends out of the conical hole (551) of the cover (55). The collet (561) is formed on the outer end of the clamping tube (56) and presses against the cover (55) in the conical hole (551) to hold a grinding element (A) in the clamping tube (56).
The protective cap (57) is mounted securely around the front end of the casing (50) to surround the rear end of the cover (55) and has a front end, a rear end and a through hole (571). The rear end of the protective cap (57) is mounted securely around the front end of the casing (50). The through hole (571) is formed through the front end of the protective cap (57) and is mounted around the cover (55) near the flange (552).
With further reference to FIGS. 7 to 9, when a user wants to draw the grinding element (A) out of the clamping tube (56), the clutch shaft (53) is rotated to make the transmitting shaft (51) move forward relative to the cover (50) and separate from the drive shaft (52). When the transmitting shaft (51) moves relative to the cover (55), the collet (561) of the clamping tube (56) will move forward relative to the conical hole (551) of the cover (55). Then, the user can draw the grinding element (A) out of the clamping tube (56) easily.
However, when the grinding element (A) draws out of the clamping tube (56), the cover (55) will move forward relative to the transmitting shaft (51) and the protective cap (57) by the spring (54) to cause the flange (552) of the cover (55) to press against the front end of the protective cap (57). When the cover (55) presses against the protective cap (57) and the transmitting shaft (51) is connected to and is rotated by the drive shaft (52) at the same time, the cover (55) and transmitting shaft (51) will get stuck with the protective cap (57) and this will cause the transmitting shaft (51) to wear.
In addition, when a user uses the conventional grinding gun to grind and polish surfaces of wood or metal, the cover (55) engages the collet (561) of the clamping tube (56) and is rotated with the transmitting shaft (51) at a high speed and this will injure the user if the user touches the rotating cover (55).
To overcome the shortcomings, the present invention provides a safe guarding assembly for a grinding gun to mitigate or obviate the aforementioned problems.